package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import com.hmdp.dto.Result;
import com.hmdp.dto.UserDTO;
import com.hmdp.entity.SeckillVoucher;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.RedisIdWorker;
import com.hmdp.utils.SimpleRedisLock;
import com.hmdp.utils.UserHolder;
import lombok.extern.slf4j.Slf4j;
import org.redisson.Redisson;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.amqp.rabbit.core.RabbitTemplate;
import org.springframework.aop.framework.AopContext;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.connection.stream.*;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import java.time.Duration;
import java.time.LocalDateTime;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 * <p>
 * 服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
@Slf4j
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {

    @Resource
    private ISeckillVoucherService seckillVoucherService;
    @Resource
    private RedisIdWorker redisIdWorker;
    @Resource
    private StringRedisTemplate stringRedisTemplate;
    @Resource
    private RedissonClient redissonClient;
    @Resource
    private RabbitTemplate rabbitTemplate;
    private static final DefaultRedisScript<Long> SECKILL_SCRIPT;
    //    //异步处理线程池
//    private static final ExecutorService SECKILL_ORDER_EXECUTOR = Executors.newSingleThreadExecutor();
    private IVoucherOrderService proxy;

    static {
        SECKILL_SCRIPT = new DefaultRedisScript<>();
        SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_SCRIPT.setResultType(Long.class);
    }

    //在类初始化之后执行，因为当这个类初始化好了之后，随时都是有可能要执行的
//    @PostConstruct
//    private void init() {
//        SECKILL_ORDER_EXECUTOR.submit(new VoucherOrderHandler());
//    }
//
//    private class VoucherOrderHandler implements Runnable {
//
//        @Override
//        public void run() {
//            while (true) {
//                try {
//                    // 1.获取消息队列中的订单信息 XREADGROUP GROUP g1 c1 COUNT 1 BLOCK 2000 STREAMS s1 >
//                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
//                            Consumer.from("g1", "c1"),
//                            StreamReadOptions.empty().count(1).block(Duration.ofSeconds(2)),
//                            StreamOffset.create("stream.orders", ReadOffset.lastConsumed())
//                    );
//                    // 2.判断订单信息是否为空
//                    if (list == null || list.isEmpty()) {
//                        // 如果为null，说明没有消息，继续下一次循环
//                        continue;
//                    }
//                    // 解析数据
//                    MapRecord<String, Object, Object> record = list.get(0);
//                    Map<Object, Object> value = record.getValue();
//                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(value, new VoucherOrder(), true);
//                    // 3.创建订单
//                    handleVoucherOrder(voucherOrder);
//                    // 4.确认消息 XACK
//                    stringRedisTemplate.opsForStream().acknowledge("s1", "g1", record.getId());
//                } catch (Exception e) {
//                    log.error("处理订单异常", e);
//                    //处理异常消息
//                    handlePendingList();
//                }
//            }
//        }
//
//        private void handlePendingList() {
//            while (true) {
//                try {
//                    // 1.获取pending-list中的订单信息 XREADGROUP GROUP g1 c1 COUNT 1 BLOCK 2000 STREAMS s1 0
//                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
//                            Consumer.from("g1", "c1"),
//                            StreamReadOptions.empty().count(1),
//                            StreamOffset.create("stream.orders", ReadOffset.from("0"))
//                    );
//                    // 2.判断订单信息是否为空
//                    if (list == null || list.isEmpty()) {
//                        // 如果为null，说明没有异常消息，结束循环
//                        break;
//                    }
//                    // 解析数据
//                    MapRecord<String, Object, Object> record = list.get(0);
//                    Map<Object, Object> value = record.getValue();
//                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(value, new VoucherOrder(), true);
//                    // 3.创建订单
//                    createVoucherOrder(voucherOrder);
//                    // 4.确认消息 XACK
//                    stringRedisTemplate.opsForStream().acknowledge("s1", "g1", record.getId());
//                } catch (Exception e) {
//                    log.error("处理pendding订单异常", e);
//                    try {
//                        Thread.sleep(2000);
//                    } catch (InterruptedException ex) {
//                        throw new RuntimeException(ex);
//                    }
//                }
//            }
//        }
//    }


    // 用于线程池处理的任务
    // 当初始化完毕后，就会去从对列中去拿信息
//    private class VoucherOrderHandler implements Runnable{
//
//        @Override
//        public void run() {
//            while (true){
//                    try {
//                        // 1.获取队列中的订单信息
//                        VoucherOrder voucherOrder = orderTasks.take();
//                        // 2.创建订单
//                        handleVoucherOrder(voucherOrder);
//                    } catch (Exception e) {
//                        log.info("处理订单异常",e);
//                    }
//            }
//        }
//    }

    public void handleVoucherOrder(VoucherOrder voucherOrder) {
        //1.获取用户
        Long userId = voucherOrder.getUserId();
        // 2.创建锁对象
        RLock redisLock = redissonClient.getLock("lock:order:" + userId);
        // 3.尝试获取锁
        boolean isLock = redisLock.tryLock();
        // 4.判断是否获得锁成功
        if (!isLock) {
            // 获取锁失败，直接返回失败或者重试
            log.error("不允许重复下单！");
            return;
        }
        try {
            //注意：由于是spring的事务是放在threadLocal中，此时的是多线程，事务会失效
            proxy.createVoucherOrder(voucherOrder);
        } finally {
            // 释放锁
            redisLock.unlock();
        }
    }

    @Override
    public Result seckillVoucher(Long voucherId) {
        // 可以多判断一下 优惠卷秒杀是否开始
        Long userId = UserHolder.getUser().getId();
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT
                , Collections.emptyList(),
                voucherId.toString(), userId.toString()
        );
        int value = result.intValue();
        if (value != 0) {
            return Result.fail(value == 1 ? "库存不足" : "不能重复下单");
        }
        long orderId = redisIdWorker.nextId("order");
        //从主线程获取代理对象
        //proxy = (IVoucherOrderService) AopContext.currentProxy();
        VoucherOrder voucherOrder = new VoucherOrder();
        voucherOrder.setUserId(UserHolder.getUser().getId());
        voucherOrder.setVoucherId(voucherId);
        voucherOrder.setId(orderId);
        rabbitTemplate.convertAndSend("seckill.direct", "seckill.order", voucherOrder);
        return Result.ok(orderId);
    }

//    //构建一个阻塞队列
////    private BlockingQueue<VoucherOrder> orderTasks = new ArrayBlockingQueue<>(1024 * 1024);
//
//    @Override
//    public Result seckillVoucher(Long voucherId) {
//        Long userId = UserHolder.getUser().getId();
//        long orderId = redisIdWorker.nextId("order");
//        Long result = stringRedisTemplate.execute(
//                  SECKILL_SCRIPT
//                , Collections.emptyList(),
//                voucherId.toString(), userId.toString()
//        );
//        int value = result.intValue();
//        if (value != 0) {
//            return Result.fail(value == 1 ? "库存不足" : "不能重复下单");
//        }
//// 保存到阻塞队列
//        VoucherOrder voucherOrder = new VoucherOrder();
//        voucherOrder.setId(orderId);
//        voucherOrder.setUserId(userId);
//        voucherOrder.setVoucherId(voucherId);
////        放入阻塞队列中
//        orderTasks.add(voucherOrder);
////        从主线程获取代理对象
//        proxy = (IVoucherOrderService) AopContext.currentProxy();
//        return Result.ok(orderId);
//    }


//    @Override
//    public Result seckillVoucher(Long voucherId) {
//        SeckillVoucher voucher = seckillVoucherService.getById(voucherId);
//        if (voucher.getBeginTime().isAfter(LocalDateTime.now())) {
//            return Result.fail("秒杀尚未开始");
//        }
//        if (voucher.getEndTime().isBefore(LocalDateTime.now())) {
//            return Result.fail("秒杀已经结束");
//        }
//        if (voucher.getStock() < 1) {
//            return Result.fail("库存不足");
//        }
//        Long userId = UserHolder.getUser().getId();
//        SimpleRedisLock lock = new SimpleRedisLock("order:" + userId, stringRedisTemplate);
//        RLock lock = redisson.getLock("order:" + userId);
//        Boolean success = lock.tryLock();
//        if(!success){
//            return Result.fail("不可以重复购买");
//        }
//       try {
//           IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
//           return proxy.createVoucherOrder(voucherId);
//       }finally {
//           lock.unlock();
//       }
//    }

    @Transactional
    public void createVoucherOrder(VoucherOrder voucherOrder) {
        Long userId = UserHolder.getUser().getId();
        Integer count = query().eq("user_id", userId).eq("voucher_id", voucherOrder.getVoucherId()).count();
        if (count > 0) {
            // 用户已经购买过了
            log.error("用户已经购买过了");
            return;
        }
        // 6.扣减库存
        boolean success = seckillVoucherService.update()
                .setSql("stock = stock - 1") // set stock = stock - 1
                .eq("voucher_id", voucherOrder.getVoucherId()).gt("stock", 0) // where id = ? and stock > 0
                .update();
        if (!success) {
            // 扣减失败
            log.error("库存不足");
            return;
        }
        save(voucherOrder);
    }
}

